Description:
The purpose of our study was to identify the native bacteria with the ability to degrade azo dyes from the rhizosphere of Sparganium erectum L., and Typha latifolia L. plants that were grown on a drain of Iran Poplin textile mill (Guilan, Iran). Eight and one strain with decolorization ability of Cibacron Brilliant Red EB and Terasil Red 3BL-01 were isolated from the saline rhizosphere of Sparganium erectum L. and latifolia L. plants, respectively. Results showed that the bacteria isolated from the rhizosphere of Sparganium erectum L. are more capable of decolorizing azo dyes than the rhizospheric bacteria of Typha latifolia L. Based on the 16S rRNA sequencing, selected strains were identified as follow: Enterobacter ludwigii strain SNP3 (OL719291), Rhodococcus fascians strain SNP5 (OL759129), Pseudomonas aeruginosa strain SNP10 (OL759126), and Bacillus safensis strain SNP13 (OL759127). The results of azo dyes biodegradation tests revealed that strains SNP10, SNP3, and SNP5 were more capable of decolorizing 97-94%, 73.8- 72.53%, and 73.5-71.13% of Cibacron Brilliant Red EB at concentration 10-20 mg/L within 72 h, respectively. Besides, strain SNP13 was the fastest strain in decolorization of Cibacron Brilliant Red EB with 68% and 59% decolorization activity at 10 and 20 mg/L respectively (24 h). Regarding Terasil Red 3BL-01, only two strains SNP3 and SNP13 could decolorize 83% and 77% of 30 mg/L of this dye, respectively. Then, the decolorization ability of strains SNP3 and SNP13 was confirmed by Thin-layer Chromatography (TLC) and Gas Chromatography (GC). For the first time, our research findings illustrated that indigenous rhizospheric bacterial strains isolated from Sparganium erectum L. plants have the potential to apply as an azo dye breakdown tool in textile effluent treatment, saline environment, and other ecosystems